dark thumb

[Katherina]

Please, help to translate.

Phrase is used in the following sentence:

“As things stand now,
I am going to be a writer.
I’m not sure that I’m going
to be a good one or even
a self-supporting one, but
until the dark thumb of
fate presses me to the dust
and says, ‘you are nothing’,
I will be a writer.”

Thanks in advance

[snezhniy]

суровый перст